Methods to estimate forest health

Abstract

Most studies made in connection with forest decline and the impact of air pollution and other environmental stresses on forests have concentrated on the assessment of crown transparency and crown discoloration in individual trees. These are non-specific indicators which are sometimes of relatively little value when determining the health of a forest ecosystem. Studies claiming to compare defoliation between different countries cannot be substantiated. Indices that could be of considerable value include a variety of visual measures of crown condition and also, several non-visual bioindicators. Some of these techniques are objective. -from Author